Power Supply Units Guide

Ready for Quad SLI

Ready for Quad SLI

With each successive generation, the power requirement of a typical enthusiast's PC goes up another notch. The emphasis today for processors may be on thermal efficiency but adding more cores to the equation is also equally popular, leading inexorably to an increase in power demands. AMD's quad core 4x4 platform is an extreme example of such a trend and makes power supplies (PSU) of 1KW and greater, a necessity rather than a luxury. Such a scenario is probably more pronounced for the graphics scene, where two GPUs in a system is no longer the cutting edge. We now have quad GPU configurations, thanks to NVIDIA's Quad SLI technology and that means up to four high-end power hungry graphics cards. The usual answer to such escalating power requirements - higher wattage PSUs.

Quad SLI Ready

Boasting a world's first for six dedicated +12V rails providing up to 18A each, this Cooler Master Real Power Pro is really geared towards multi-GPU configurations. Suitable for both NVIDIA's SLI or ATI's CrossFire, it is however clearly targeted at Quad SLI due to the presence of the four individual six-pin PCIe Molex power connectors. With these, you will no longer need to use the Molex power converters that come with your graphics cards.

Having tried Quad SLI, normal SLI and CrossFire setups on a high-end Core 2 Duo system with the Cooler Master Real Power Pro 850W PSU, we have to say that so far, we have had no power related issues, like insufficient power to the +12V rails for example. The graphics cards themselves have performed as expected and as they say, no news is good news. The PSU kept a low noise and heat profile (it has an internal 135mm smart fan with variable speed control and a typical decibel rating of less than 16dBA) during prolonged usage. Although our observations are mostly anecdotal and 'unscientific', this PSU does appear to work as advertised.

As part of the new ATX V2.2 standard, the current for the +5Vsb rail, used for your USB devices has been increased in the Cooler Master Real Power Pro 850W from 2A to 3.5A. This means that you need not worry about insufficient power for your USB ports and Cooler Master claims that this PSU can support up to 10 - 12 devices. You could even charge your USB devices when the PC is turned off.

Efficient but not Modular

Many branded PSUs now are going the thermal efficiency route and being a high-end flagship model from Cooler Master, the Real Power Pro 850W has all these features, from a 99% Active PFC (power factor correction) rating and an efficiency of more than 85%.

There are also various standard built-in protection measures, like over-voltage, under-voltage and over-temperature, overloading and short circuit protection, whereby the PSU will stop working in such instances to protect your motherboard and other hardware components against electrical damage.

However, there's another important trend that Cooler Master did not include in this powerful PSU. No modular cabling! This is especially important for powerful and high-end PSUs, where there are usually more than sufficient power connectors. Not all of them may be utilized at the same time and modular cables would have allowed users to hook up only those that they require. For example, you may get this PSU in anticipation of a Quad SLI in the future but for now, you may only need SLI, in which case, modular cables allow you to do away with two extra PCIe power connectors to save space and ease up on cable management.

Always On?

Unlike most good PSUs, this PSU doesn't have a power switch at the rear. This means that you will have to switch off your mains to turn off the PSU properly. This could be an issue when you're fooling around with the motherboard. For example, it is always recommended to turn off the PSU when clearing the CMOS on the motherboard and it is certainly more troublesome if you can't just switch off the PSU with the flick of a button at its back. Users may also forget this step due to the lack of such a switch and that may have negative consequences for your system. Cooler Master reasons that since this a high wattage PSU, the transient inrush current can be excessively large, generating high temperatures that can damage normal power switches. They state that switches that are reliable and safe enough for this use are not easy to come by, thus their reason to do away with a power switch.

Final Thoughts

Cooler Master's 850W monster may not be the first of such powerful PSUs and probably overshadowed by the 1KW behemoths in the market but for most enthusiasts, the name of the game is not always about raw power. Cost is also a factor and 1KW is frankly overkill for virtually most home user PCs. As you can see, 850W is sufficient for a Quad SLI setup and unless you're packing a server cum ultimate gaming machine, we don't know why you need more at this point in time. At about US$219, the Cooler Master Real Power Pro 850W will probably be too much even for some enthusiasts but given its capability, it's definitely worth considering at such a price.